I have polygons containing an attribute to be summed by a polygon grid. the polygons with the attribute always share borders with each grid cell and never extend outside any grid cell (the grid has been used to 'union' the polygons prior).
I am having trouble in ArcMap 10.x getting the 'spatial join' tool using the 'intersect' or 'have their center in' or 'within' match options to assign the sum of the attributes of polygons within each grid cell to an attribute of the grid cell. I think this may be because of share borders, though the 'select by location' tool using 'within' will select the desired polygons.
The layers are the same projection and in the same geodatabase. Also have set the 'merge rule' parameter of the field to 'sum' in the 'spatial join' tool.
The only work-around I've found is to use 'spatial join' tool with the 'intersect' match option and a 'search radius' set to a negative such as -100 meters.